CVE-2025-11234VulnerabilityPublished 23 Feb 2026Updated 5 Nov 2026

Red Hat Security Advisory: qemu-kvm security update

Affects Red Hat qemu-kvmSource GCVE Database

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Authoritative record:CVE-2025-11234· High 7.5

Not known to be exploited · CVSS 7.5 High : upgrade Red Hat qemu-kvm to 10.1.2 soon.

Data as of 5 Nov 2026, 16:03 UTC

CVSS 3.1 base score

7.5High

How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none

CVSS scores by source
CNA (redhat)	CVSS 3.1	7.5

Patch: Available – fixed in 10.1.2

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: High

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 3 Oct 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 5 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade qemu to 10.1.2.

Affected software

Product	Affected	Fixed in
qemu	Affected >=2.6.0 <10.1.2	Fixed in 10.1.2

AI-suggested

Red Hat has released updated qemu-kvm packages for Red Hat Enterprise Linux 9.2 and its variants that address CVE-2025-11234. Users should apply these official security updates as described in Red Hat's advisory and article (https://access.redhat.com/articles/11258) to remediate the vulnerability. No additional mitigation steps are indicated by the vendor advisory.

Description

A use-after-free vulnerability exists in the VNC WebSocket handshake implementation of qemu-kvm, a user-space component for running virtual machines with Kernel-based Virtual Machine (KVM) on Linux. This vulnerability is identified as CVE-2025-11234 and has been rated with moderate security impact by Red Hat. The issue affects Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions and related variants. A security update addressing this vulnerability is available from Red Hat.

Impact

The vulnerability is classified as moderate in severity by Red Hat Product Security. Use-after-free bugs can lead to memory corruption, which may be exploitable to cause denial of service or potentially arbitrary code execution, depending on the context. However, no known exploits in the wild have been reported. The impact is limited to environments using the affected qemu-kvm versions with VNC WebSocket functionality enabled.

Summary

The qemu-kvm package, which provides the user-space component for KVM virtualization on Linux, contains a use-after-free vulnerability in the VNC WebSocket handshake process (CVE-2025-11234). This flaw could potentially lead to memory corruption issues during the handshake phase of VNC WebSocket connections. Red Hat has issued a security advisory (RHSA-2026:3077) describing this vulnerability and providing updated packages to remediate the issue. The advisory covers Red Hat Enterprise Linux 9.2 variants including x86_64, ppc64le, aarch64, and s390x architectures.

CWE-416Use After Free (opens in a new tab)
Variant weaknessLikelihood of exploit: HighCWE Top 25 (2025): #7
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.
Architecture and Design · Language Selection
Choose a language that provides automatic memory management.
Implementation · Attack Surface Reduction
When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.
OWASP Cheat Sheets
XML Security (opens in a new tab)
Mass Assignment (opens in a new tab)
OWASP ASVS 4.0.3
V13.3.1 (opens in a new tab)
V5.1.4 (opens in a new tab)
V5.1.3 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 5 Nov 2026, 16:03 UTC

WeaknessesCWE-416

Technical details

References

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